Analog variable-frequency controller and switching converter therewith

A switching converter comprising:

• an output circuit;
• a feedback circuit, for generating a first pulse width modulation signal according to the operating state of said output circuit;
• a current sensor, for detecting said output circuit to output a load current signal;
• an analog variable-frequency controller comprising:
• a first current generator, for receiving said loading current signal and outputting a corresponding first voltage signal;
• a second current generator, for receiving said loading current signal and outputting a corresponding second voltage signal;
• a clock generator, for generating a corresponding switching frequency signal based on said first voltage signal or said second voltage signal;
• and
• a light/heavy load selector, electrically connected to said first current generator, said second current generator and said clock generator, and for receiving a control signal to control said clock generator to select receiving said first voltage signal or said second voltage signal;
• and
• a first SR latch, comprising a R terminal receiving said first pulse width modulation signal, a S terminal receiving said switching frequency signal, and an output terminal outputting a second pulse width modulation signal to control said operating state of said output circuit.